1. Field of the Invention
The present invention relates to window glass for a vehicle, and a glass antenna. The window glass includes the glass antenna for transmitting and receiving communication waves.
2. Description of the Related Art
Recently, with the development of communication technology, a mobile device is carried in a vehicle to execute communication between the vehicle and the mobile device, and between the vehicle and outside the vehicle.
Further, technology of a so-called connected car has been proposed that includes a function of the vehicle itself to collect information from outside, and a function of the vehicle itself to deliver information. With a connected car, by bi-directionally communicating, for example, data transmitted from the vehicle, such as location information, a vehicle condition, and a road condition; and map information, traffic information, and weather information collected from outside; telematics service can be provided, such as traffic congestion mitigation and driving assist for enhancing efficiency and safety of the vehicle. Furthermore, it is expected that, with the connected car, solution/services, etc., can be provided, such as music and video delivery services, as a tool (device) to enhance convenience of a user.
For such communication waves that are used for bi-directional communication, used frequencies differ depending on countries, and in a specific country, used frequency bands differ depending on operators. Thus, an antenna that supports a wide band is preferable, so that a plurality of communication waves can be received.
Here, as illustrated in FIG. 1, a technique has been proposed to install a communication antenna on a roof of the vehicle, so that a bi-directional communication function between the vehicle and outside the vehicle can be achieved.
In the example illustrated in FIG. 1, an antenna unit 80 having a diversity structure that includes a first antenna 81 and a second antenna 82, which are installed to stand on a ground plate 83 while separated in the longitudinal direction (front-back direction) of the vehicle 90, is installed on a roof 91 of a vehicle 90. These antennas 81 and 82 are built into a case 84.
Additionally, for a vehicle, various types of technology of a glass antenna, which is window glass including an antenna function, have been proposed to receive radio or television signals. For example, a glass antenna 70 according to Patent Document 2, which is illustrated in FIG. 2, can receive digital audio broadcast signals.